CN203811991U - Additive manufacturing system for printing three-dimensional parts - Google Patents

Abstract

An additive manufacturing system (10) for printing three-dimensional parts comprises transfer media (14, 114 and 214) configured to receive layers (18, 128 and 228) from an imaging tool (12), heaters (32, 132 and 232) configured to heat the layers (28, 128 and 228) on the transfer media (14, 114 and 214) and layer transmission assemblies (33, 133 and 233), wherein the layer transmission assemblies comprise building platforms (18, 118 and 218) and are configured to transfer the heated layers (28, 128 and 228) onto the building platforms (18, 118 and 218) layer by layer to print three-dimensional parts (22, 122 and 222).

Description

For printing the accumulation manufacturing system of three-dimensional part

Technical field

Present disclosure relates to for building the accumulation manufacturing system of three-dimensional (3D) parts and supporting construction.Especially, present disclosure relates to for adopting imaging processing, as electrophotography, builds the accumulation manufacturing system of 3D parts and supporting construction.

background technology

Accumulation manufacturing system is used for adopting one or more accumulation manufacturing technologies to build 3D parts from the numeral of 3D parts (as, STL formatted file).The example of commercially available accumulation manufacturing technology comprises technology, ink jet, selective laser sintering, the injection of powder/cementing agent, electron-beam melting and the 3 D plane printing technique based on extruding.For each in these technology, the numeral of 3D parts is divided into a plurality of flat seams at first.The layer being divided into for each, produces tool path subsequently, and its instruction that is provided for specific accumulation manufacturing system is to form to given layer.

For example, in the accumulation manufacturing system based on extruding, can mobile parts material by extruding, according to the numeral of 3D parts, in mode successively, print 3D parts or model.The extruding end that component materials carries by the printhead by this system is extruded, and is deposited on the substrate in x-y plane as series of road.The component materials of extruding is fused to the component materials of previous deposition, and solidifies when temperature declines.Then printhead increases progressively along z axle (perpendicular to x-y plane) with respect to the position of substrate, and repeats subsequently this process to form the 3D parts of copying described numeral.

When manufacturing 3D parts by the layer of means of deposition material, supporting layer or structure be conventionally structured in the teat that do not supported by component materials itself below or in the cavity of constructed object.Can utilize the identical deposition technique that means of deposition material adopts to build supporting construction.Main frame produces with the additional geometry that acts on the outstanding or free space supporting construction partly of the 3D parts that are just being formed.During printing technique, according to produced geometry, from second nozzle, deposit propping material subsequently.Propping material adheres to modeling material during manufacture, and is printing when technique completes and can remove from completed 3D parts.

In two dimension (2D) is printed, electrophotography (that is, static dump art) is for form the ordinary skill of 2D image in flat substrate (as at printer paper).Electrophotographic system comprises the conductive supporting cylinder that is coated with photoconductive material layer, wherein, by charging and by light source, photoconductive layer being carried out to image direction exposure subsequently, forms the electrostatic image that hides.The electrostatic image that hides is moved into development station subsequently, and the charging zone that toner is applied to photoconductive insulator on development station is to form visual picture.Formed toner image be transferred to subsequently substrate (as, printer paper) and by heat or pressure fixing to substrate.

Summary of the invention

An aspect of present disclosure relates to a kind of for printing the accumulation manufacturing system of three-dimensional part.This accumulation manufacturing system comprises and is configured for the transfer medium that receives and shift the imaging layer of thermoplastic based powders from imaging tool, and is configured for the imaging layer on transfer medium is heated to at least well heater of the temperature of fusion of thermoplastic based powder.This system also comprises: the layer that comprises construction platform transfers assembly, and wherein this layer transfers assembly and is configured in mode successively zone of heating is transferred on construction platform with printing three-dimensional part.This system also comprises cooling unit, its be configured on one's own initiative cooling transferred layer the three-dimensional part of having printed is remained on to the averaging section temperature place of the deformation temperature that is less than about greatly three-dimensional part.

Another aspect of present disclosure relates to a kind of for printing the accumulation manufacturing system of three-dimensional part, this accumulation manufacturing system comprises and is configured for the rotatable band receiving from the developing layer of electrofax instrument, and be configured for by rotatable with on developing layer be heated at least well heater of the temperature of fusion of thermoplastic based powder.This system also comprises transfers element and construction platform, and construction platform is configured for to receive zone of heating and adopt from rotatable band and transfers element and transfer zone of heating to print 3D parts at construction platform in mode successively.This system also comprises cooling unit, this cooling unit be configured on one's own initiative cooling transferred layer approximately to remain on the averaging section temperature place lower than the deformation temperature of 3D parts by printing 3D parts.

Another aspect of present disclosure relates to a kind of for adopting accumulation manufacturing system to print the method for three-dimensional part.The method comprises from thermoplastic based powder carries out imaging to the layer of three-dimensional part, and imaging layer is transferred to transfer medium, and when being maintained on transfer medium, heats imaging layer at imaging layer.The method also comprises transfers the surface to three-dimensional part by zone of heating, from transfer medium, discharge and transferred layer, make to be transferred layer and keep adhering to three-dimensional part, and the cooling layer that transferred is to remain on the three-dimensional part of having printed at the averaging section temperature place of the deformation temperature that is less than about greatly three-dimensional part.

In certain embodiments, accumulation manufacturing system is configured for the fast speed of the passive heat rate of diffusion than 3D parts and prints or otherwise manufacture layer.

Definition

Except indicating in addition, the implication hereinafter providing is provided following term as used in this article:

Term " transfers (transfusion) ", and " by transferring ", " just transferring " waited to relate to and utilized heat and pressure adhesion layer, the polymer molecule phase counterdiffusion at least in part of wherein said layer.

Term " transfers pressure " and relates to during transferring step, as applied pressure when the layer of 3D parts is transferred together.

" deformation temperature " of term 3D parts relate to 3D parts enough softening make as follow-up during transferring step follow-up apply transfer the structural intergrity that pressure overcomes 3D parts, thereby the temperature while making 3D part distortion.

Except indicating in addition, the temperature relating to is herein based on being greater than pressure (that is a, atmospheric pressure).

Such as " top ", " below ", " top ", the direction orientation that wait and so on " bottom " is what to take along the direction of the print axis of 3D parts be reference.Print axis is in the embodiment of vertical z axle therein, and layer Print direction is the upward direction along vertical z axle.In these embodiments, term " top ", " below ", and " top ", wait based on vertical z axle " bottom ".Yet, along different axis, print in the embodiment of layer of 3D parts therein, term " top ", " below ", and " top ", " bottom " grade is relevant to given axis.

Term " provides ", as for " material is provided " etc., when being quoted in the claims, is not any special transmission or the reception that the project that provides is provided intention.Exactly, for object clear and that easily read, term " provides " in the subsequent element that is only used for being set forth in claim the project being related to.

Term " approximately " and " substantially " be in this article about result from expection well known by persons skilled in the art change (as, the restriction in measurement and changeability) measurable magnitude and scope used.

Accompanying drawing explanation

Fig. 1 is that the layer comprising of present disclosure with pressing plate transfers the schematic diagram of the accumulation manufacturing system based on electrophotography of assembly.

Fig. 2 receives the top view of the construction platform of zone of heating, illustrates air knife configuration.

Fig. 3 is the quantity of printable layer and the diagram of the relation between averaging section temperature of 3D parts, the line chart of the 3D parts of printing while showing the 3D parts printed while there is no active cooling and active cooling.

Fig. 4 A-4D is the zoomed-in view that layer transfers assembly, illustrates the layer transfer technology of present disclosure.

Fig. 5 A-5E is the zoomed-in view that the replaceable layer with mip rolls of the accumulation manufacturing system based on electrophotography transfers assembly, illustrates layer transfer technology.

Fig. 6 A-6F is zoomed-in view that independent another the replaceable layer that transfers roller and discharge roller of having of accumulation manufacturing system based on electrophotography transfers assembly, illustrates layer transfer technology.

Fig. 7 is zoomed-in view that another replaceable layer that having of accumulation manufacturing system based on electrophotography can enclosed cavity transfers assembly.

Fig. 8 is the local side of rotatable transition zone.

Fig. 9 A is the top view of the first embodiment with the rotatable transition zone of receiving area and scrambler mark.

Fig. 9 B is the top view having for the second embodiment of the rotatable transition zone in the hole with traction feeding mode combination.

Fig. 9 C is the backplan having for the 3rd embodiment of the rotatable transition zone of the rear flank with the combination of Timing Belt mode.

Figure 10 is the process flow diagram of the first implementation method of the layer transfer technology of present disclosure, and what this implementation method had a combination transfers step and fixing step and active cooling step.

Figure 11 is the process flow diagram of the second implementation method of layer transfer technology, and this this implementation method has independent step and the fixing step of transferring, and optional active cooling step.

Figure 12 is the process flow diagram of the 3rd implementation method of layer transfer technology, and this this implementation method has parts surface heating steps, independent step and fixing step and the active cooling step of transferring.

Embodiment

Present disclosure relates to for print the layer transfer technology of 3D parts and supporting construction in mode successively, wherein can thermal control mode printing every one deck from parts or propping material.Use imaging system, as used the accumulation manufacturing system based on electrophotography, execution level transfer techniques.For example, can adopt electrophotography every one deck that develops, and by transfer medium (as, rotatable band or cylinder) from electrofax (EP) instrument, carry every one deck.Subsequently this layer is transferred to construction platform, thereby prints 3D parts (or supporting construction) in mode successively, wherein continuous layer is transferred to make 3D parts (or supporting construction) together.

Print and compare with 2D, in 2D prints, by arranging electromotive force through printer paper, the toner-particle having developed can be transferred to printer paper statically, in 3D environment, the multilayer of having printed print layer to determined number (as, approximately 15 layers) electrostatic transfer of peventing member and propping material effectively afterwards.Instead, in this disclosure, the layer being kept by transfer medium is heated at least temperature of fusion of layer material.Subsequently zone of heating is squeezed in to the layer upper (or to construction platform) of previously having printed, thereby transfers together described layer (that is, transferring step).This allows vertically member multilayer 3D parts and supporting construction, surpasses otherwise via the attainable scope of electrostatic transfer.

As discussed below, temperature of fusion be enough to by layer material be melted to polymer molecule that molten state makes layer material follow-up transfer step during at least in part phase counterdiffusion with promoting layer between or interface-cross-linked temperature.Temperature of fusion is enough high transfers with promoting layer, but temperature may be too hot for being transferred layer and can not discharge neatly or otherwise peel off from transfer medium.This can cause a part of being transferred layer to keep adhering to transfer medium potentially, or is making dirty when transfer medium discharges, and feature details, dimensional accuracy and the porosity of 3D parts printed in this negative impact.

Thereby in certain embodiments, layer transfer technology can also comprise " fixing step ", wherein before being transferred layer from transfer medium release, cooling transfer medium and/or quilt are transferred layer.Although be not wishing to be bound by theory, but it is believed that the cooling transfer medium of this fixing step and transferred the interface between layer, therefore being transferred layer to the surperficial bounding force of transfer medium with quilt compares, increase the bounding force of the mutual propagate polymerization thing in adjacent layer, thereby the layer that transferred that adheres to 3D parts is maintained in fixed space position.This allows to be transferred layer and discharges neatly and keep adhering to 3D parts from transfer medium.

And, due to imaging system can with than heat, diffuse through 3D parts can variable resistance the fast a lot of speed printable layer of speed, therefore at 3D parts, observe heat built-up.Like this, along with the high growth of given 3D parts, the heat dissipation that is derived from passive heat diffusion becomes and is not enough to cooling zone of heating.Interval velocity is faster, and the heat built-up in the main body of 3D parts is faster.Along with printing continuously continuous layer, this heat built-up may surpass the deformation temperature of 3D parts, causes that the main body of 3D parts is enough softening, has reduced its structural integrity.This soft parts follow-up transfer step during follow-up transferring under pressure of applying may be out of shape.

In certain embodiments, by slowing down, print technique and can reduce heat built-up.As can be appreciated, this can increase and print the 3D needed time of parts considerably, thereby reduces turnout.Instead, in order to overcome this problem, maintain fast printing speed, layer transfer technology can comprise for preventing that 3D parts from gathering " the active cooling step " of additional heat simultaneously, thereby 3D parts are maintained lower than lower " the averaging section temperature " of the deformation temperature of 3D parts and located.

Especially, after transferring every one deck of 3D parts, from transferred heat that layer is added into 3D parts be substantially removed before the transferring of one deck.This remains on averaging section temperature by 3D parts, described averaging section temperature by balance satisfactorily to promote layer-to-layer adhesion and to reduce curling effect, simultaneously also enough low to prevent 3D parts softening too much (that is, lower than its deformation temperature).

As shown in Figure 1, system 10 is that it is in conjunction with the layer transfer technology of present disclosure for adopting electrophotography to print the exemplary accumulation manufacturing system of 3D parts and supporting construction.System 10 comprises for printing EP instrument 12, transition zone 14, a plurality of roller 16, construction platform 18 and the pressing plate 20 of 3D parts (as, 3D parts 22) and any supporting construction (not shown) being associated.The example of the feature operation of the parts of applicable system 10 comprises those disclosed in U.S. Patent Application No. 13/242,669 and 13/242,841.

In alternative embodiment, system 10 can comprise the different imaging tool for described layer is carried out to imaging.As discussed below, layer transfer technology concentrates on layer from the transfer to construction platform 18 with 14 (or other transfer mediums), and layer is to the transfer with on 14, rather than concentrates in specific imaging tool.Yet, layer transfer technology is suitable especially for the accumulation manufacturing system based on electrophotography (as, system 10), as mentioned above, wherein after giving the layer of determined number, print the multilayer of having printed in the 3D environment electrostatic transfer of peventing member and propping material on one's own initiative.

System 10 also comprises controller 24, described controller 24 is one or more control circuits, microprocessor-based tool control system, and/or digital controlled formula grating image processes or system, and it is configured to print command based on receiving from main frame 26 with the parts of method of synchronization operating system 10.Main frame 26 is to be configured for to communicate by letter to provide print command one or more computer based systems of (with other operation information) with controller 24.For example, main frame 26 can by 3D parts 22(and any supporting construction) the relevant information of layering be passed to controller 24, thereby permission system 10 is printed 3D parts 22 in mode successively.

As such in what discuss in U.S. Patent Application No. 13/242,669 and 13/242,841, EP instrument 12 is configured to adopt the successive layers 28 of electrophotography development thermoplastic based powder.As used in this article, term " electrophotography " comprises ionography.Thermoplastic based powder comprises one or more thermoplastics (as, acrylonitrile-butadiene-styrene (ABS) (ABS) multipolymer), and can comprise that one or more are for adopting EP instrument 12 to develop and to the supplementary element of the friction electric attraction with 14.

The developing layer 28 of thermoplastic based powder turns to the first transport zone subsequently, in the first transport zone middle level 28, from EP instrument 12, is transferred to and is with 14.Be with 14 to be exemplary transfer mediums, for developing layer 28 being shifted or be otherwise delivered to construction platform 18 from EP instrument 12 under the help at pressing plate 20.In the illustrated embodiment, be with 14 to comprise front or transitional surface 14a and rear or surface in contact 14b, wherein front surface 14a is towards EP instrument 12.As discussed below, in certain embodiments, being with 14 can sandwich tape, has the low-surface-energy film that limits front surface 14a, and is arranged on the base portion that limits rear surface 14b.

System 10 can also comprise bias mechanism 29, and described bias mechanism 29 is configured to for inducting through the electromotive force with 14 so that the layer 28 of thermoplastic based powder is electrostatically attracted to and is with 14 from EP instrument 12.Because each layer 28 thickness now in this technique is individual layer increment, so electrostatic attraction is applicable to layer 28 to be transferred to and to be with 14 from EP instrument 12.Yet, as mentioned above, after the layer 28 of printing to determined number, a plurality of printable layers 28 of 3D parts 22 optionally preventing layer 28 from 14 electrostatic transfer to construction platform 18.

A plurality of rollers 16 are a series of driven rollers and/or idler roller or the pulleys that are configured to the tension force on retainer belt 14 when rotating in the sense of rotation of arrow 30 with 14.This allows to maintain when in conjunction with construction platform 18 and pressing plate 20 with 14 the orientation of general planar.System 10 can also comprise service loop (not shown), as those disclosed in U.S. Patent Application No. 13/242,841.

System 10 also comprises well heater 32, the sense of rotation based on 14, and well heater 32 is positioned at the upstream of construction platform 18 and pressing plate 20.Well heater 32 is to be configured to, before arriving pressing plate 20, layer 28 is heated to at least one or more heating arrangements of the temperature of fusion of thermoplastic based powder.The example that is applicable to the device of well heater 32 comprise contactless radiation heater (as, infrared heater or microwave applicator), convection heating system (as, heating hair-dryer), contact-type heating device (as, warm-up mill and/or platen), their combinations etc., wherein contactless radiation heater is preferred.Wish that every one deck 28 is through (or passing through) the sufficiently long residence time of well heater 32, layer 28 is heated to the temperature of fusion of expection.

As defined above, temperature of fusion is thermoplastic based powder to be melted to fully to the temperature of molten state.Therefore, temperature of fusion will change according to used certain material.For example, for Acrylonitrile Butadiene-Styrene copolymer material, the scope of temperature of fusion can be that this depends on specific copolymer composition from approximately 180 ℃ to approximately 220 ℃.Warming thermal plastic based powders there is no need to require every kind of composition of thermoplastic based powder all to melt.Exactly, whole thermoplastic based powder need to reach molten state, for follow-up, transfers.This is usually directed to be melted to fully one or more thermoplastics of the thermoplastic based powder of fusible state.

Construction platform 18, pressing plate 20 and well heater 32 can be jointly called layer and be transferred assembly 33.Layer transfers assembly 33 and is configured in mode successively zone of heating 28 from 14 layers (or to construction platforms 18) that previously transferred that transfer to 3D parts 22.

Construction platform 18 is that being configured for of system 10 receives zone of heating 28 for print platform assembly or the platen of 3D parts 22 in mode successively.Construction platform 18 is supported by z pillow block frame 34, and z pillow block frame 34 is to be configured to after each compression step along vertical z axle with respect to 14 and the pressing plate 20 linear guide mechanism that little by little reduces construction platform 18.Adopting the movement of 34 pairs of construction platforms 18 of z pillow block frame is the command operations based on carrying out self-controller 24 by z axle motor 36, and wherein z axle motor 36 can be electro-motor, hydraulic system, baric systerm etc.

In the illustrated embodiment, construction platform 18 can be by heating element 38 (as, electric heater) heating.Heating element 38 is configured for heating construction platform 18 and construction platform 18 is maintained to the rising temperature place that is greater than room temperature (25 ℃), as desired the averaging section temperature of 3D parts 22.This allows construction platform 18 to help 3D parts 22 to maintain this averaging section temperature place.

As mentioned above, the averaging section temperature of wishing 3D parts 22 is enough high to promote layer-to-layer adhesion and will reduce curling effect, simultaneously also enough low to prevent 3D parts 22 softening too much (that is, lower than its deformation temperature).Be applicable to the scope of averaging section temperature of 3D parts 22 from the average solidification temperature of thermoplastic that is greater than thermoplastic based powder to the about glass transformation temperature of thermoplastic.More desirably, averaging section temperature is maintained at the creep relaxation temperature place of the thermoplastic of about thermoplastic based powder, or in creep relaxation temperature up and down in the scope of approximately 10 ℃.The example that is applicable to the creep relaxation temperature of definite material is disclosed in the people's such as Batchelder U.S. Patent number 5,866,058.

For example, when printing the layer 28 of Acrylonitrile Butadiene-Styrene copolymer based powders, the averaging section temperature of 3D parts 22 can be about 100 ℃.This averaging section temperature allows 3D parts 22 in the follow-up structural intergrity that maintains it while being compressed between construction platform 18 and pressing plate 20 during transferring step.And, when the top layer of 3D parts 22 is maintained at the zone of heating 28 at this temperature place the temperature place of reception in the temperature of fusion of approximately 200 ℃, for transferring together the interface temperature that transfers of layer, at approximately 150 ℃, locate to start.Phase counterdiffusion is interface-cross-linked to promote at least in part for the polymer molecule of the applicable layer 28 of this temperature.

Pressing plate 20 is exemplary heatable elements or can transfers component element by zone of heating, its be configured for during each transfers step by with 14 and given zone of heating 28 be pressed against downwards on 3D parts 22 and construction platform 18.Can activate pressing plate 20 by being configured to the servo control mechanism (not shown) along vertical z axle moving press plate 20 during each transfers step.

The specified pressure that hope applies during each transfers step is enough high so that zone of heating 28 is adhered to layer 28 (or to the construction platform 18) that previously transferred, and allows polymer molecule phase counterdiffusion at least in part.Yet, also wish that balance transfers pressure and push too much 3D parts 22 to prevent pressing plate 20, thereby allow 3D parts 22 to maintain its dimensional integrity.

In the illustrated embodiment, pressing plate 20 is can be by heating element 40 (as, electric heater) heating.Heating element 40 is configured for heated platen 20 and pressing plate 20 is maintained to the rising temperature place that is greater than room temperature (25 ℃).Yet, to compare with the upper high-temperature of construction platform 18, heating element 40 can heat and maintain pressing plate 20 at the temperature place of averaging section temperature that is less than the expectation of 3D parts 22.For example, the averaging section temperature of the expection of 3D parts 22 is therein that in the situation of 100 ℃, heating element 40 can heat and maintain pressing plate 20 and locate at approximately 70 ℃.

The lower temperature of pressing plate 20 will be from rear surface 14b side salband 14 (that is, fixing step).As mentioned above, if transferred layer 28, keep too hot, may keep adhering to the front surface 14a with 14, rather than discharge neatly from being with 14.Like this, by the contact salband 14 from pressing plate 20, allow front surface 14a and the quilt of salband 14 fully to be transferred the interface between layer 28, to discharge neatly and to be transferred layer 28 from being with 14.

On the other hand, due to 14 and pressing plate 20 between large contact surface area, if by pressing plate 20 maintain too low temperature (as, 25 ℃), pressing plate 20 is with 14, the duration of contact during transferring step may be transferred layer 28 cooling obtaining too much, thereby reduce, transfer interface temperature, this can reduce interlayer adhesion force.Like this, in certain embodiments, wish that temperature that heating element 40 maintains these competition thermal effect of balance by pressing plate 20 sentence and be convenient in single combination step, transfer simultaneously and fix.

System 10 can also comprise one or more air knives 42 or other cooling unit, and wherein air knife 42 is configured to Local cooling air to blow to the exemplary cooling unit of the top layer of 3D parts 22.As illustrated best in Fig. 2, the cross side that air knife 42 is positioned to contiguous construction platform 18 is with the guiding cooling air laterally of the moving direction with respect to 14.This allows air knife 42 to extend along the whole length of 3D parts 22, on the top layer of 3D parts 22, comprises fused layers 28, and good air-flow is provided.In alternative embodiment, system 10 can also comprise second air knife 42 (not shown) at the contrary cross side place that is positioned at construction platform 18.In thering is the embodiment of air knife 42 or other cooling unit.Pressing plate 20 can be heated to temperature of fusion to promote to transfer the phase counterdiffusion in step.Subsequently, when discharging pressing plate 20, by from be with 14 releases transferred layer before the cooling layer that transferred, can carry out independent fixing step.

As mentioned above, when system 10 is during with high speed printing layer 28, printable layer 28 did not have time enough to be cooled to the averaging section temperature of expectation before printing follow-up layer 28.Like this, along with the growth of the height of 3D parts 22, the heat dissipation that is derived from passive heat diffusion becomes and is not enough to cooling zone of heating.

This has been illustrated in Fig. 3, the quantity of printable layer and the diagram of the relation between averaging section temperature of the 3D parts (being represented by line 46) that Fig. 3 prints while being the 3D parts (being represented by line 44) printed during about active cooling not and active cooling.As shown in line 44, in the situation that not there is not active cooling, the heat being added by the every one deck in its temperature of fusion place will accumulate in 3D parts, cause that averaging section temperature increases, until reach the deformation temperature of 3D parts, and as shown in threshold line 48.At threshold line 48 places, the enough height of temperature in the main body of 3D parts make component materials substantially softening.When 3D parts reach this, by pressing plate 20 follow-up apply during transferring step transfer the structural intergrity that pressure may overcome 3D parts, thereby make 3D part distortion.

Yet, air knife 42 after transferring step on one's own initiative cooling every one deck to prevent additional heat accumulation.As shown in line 46, active cooling has been provided by heat substantially that provided by every one deck 28, thereby after printable layer 28, provides the heat built-up that is roughly zero at each.Like this, during whole printing, substantially 3D parts 22 can be maintained to the averaging section temperature place lower than its deformation temperature.

In certain embodiments, maybe advantageously the enough height of averaging section temperature make the main body of 3D parts 22 present a small amount of softening.Have been found that the main body when 3D parts 22 presents a small amount of softening, while still maintaining its total globality, utilize the follow-up of pressing plate 20 to transfer the main body that step can leniently be pushed 3D parts 22, thereby increase component density.The component density increasing correspondingly reduces fragility and the porosity of produced 3D parts 22, and increases its z axle intensity.These characteristics are benefited to multiple application.

Although adopt air knife 42 to be illustrated, but alternatively, system 10 can comprise and multiplely different is configured to after each transfers step on one's own initiative cooling every one deck to prevent the cooling unit of additional heat accumulation, as refrigeration unit, liquid cooling unit etc.And one or more air knives 42 (or other cooling unit) can be positioned near other position construction platform 18 and pressing plate 20, cooling-air is guided into the top layer of 3D parts 22.Optionally, system 10 can also comprise for each follow-up transfer step before by the top layer of 3D parts 22 or surface heating to the additional heater of temperature of fusion (as, well heater 270 and 272, at Fig. 6 A-6F).

Fig. 4 A-4D illustrates the example process for system 10 printable layers 28 of the layer transfer technology by employing present disclosure.When printing starts, construction platform 18 and pressing plate 20 can be heated to their target temperature.For example, construction platform 18 can be heated to the averaging section temperature of the expectation of 3D parts 22, and pressing plate 20 can be heated to the temperature lower than the averaging section temperature of the expectation of 3D parts 22.

Printing relates at first with EP instrument 12 (shown in Figure 1) developing layer 28 and via being with 14 developing layer is transferred to well heater 32.As shown in Figure 4 A, when developing layer 28 processes (or passing through) well heater 32, well heater 32 is heated at least temperature of fusion of thermoplastic based powder by layer 28 and the relevant range with 14.

As shown in Figure 4 B, with 14, the continuous rotation in the direction of arrow 30 aligns the zone of heating 28 on construction platform 18 along x axle and suitable registration position.Pressing plate 20 subsequently can downward actuating as shown in arrow 50, so that zone of heating 28 is pressed on the layer of previously having printed of 3D parts 22.As shown in Figure 4 C, because layer 28 is at least heated to the temperature of fusion of component materials, be therefore extruded layer 28 and transfer to the top surface of 3D parts 22.

The scope that is adapted at transferring the example of the duration that step pushes is from approximately 0.1 second to approximately 1.0 seconds, and the scope of specially suitable duration is from approximately 0.1 second to approximately 0.5 second.In certain embodiments, the extruding duration is fixed values to every one deck 28.In alternative embodiment, the extruding duration can size and geometry based on 3D parts 22 change.For example, the extruding duration can reduce for the layer 28 with less cross-sectional area and/or fine-feature details, as discussed below.

Pressing plate 20 lower than the averaging section temperature of expectation and substantially lower than the temperature of temperature of fusion, start to absorb heat from the heating region with 14.As mentioned above, this is by helping release to be transferred layer 28 from rear side 14b salband 14.

After transfer/fixing step completes, pressing plate 20 can be as shown in arrow 52 be upwards retracted, and to discharge, is applied to 14 and is transferred the pressure of layer 28.In the embodiment shown in Fig. 4 D, this will be transferred layer 28 from being with 14 releases, allow to be transferred layer 28 and keep being transferred to 3D parts 22.In addition, z pillow block frame 34 can reduce construction platform 18 downwards as individual layer increment, as shown in arrow 54.

In alternative embodiment, pressing plate 20 can be heated to temperature of fusion to help transferring of layer 28.In this embodiment, wish that layer transfers assembly 33 and is configured to make the pressing plate 20 of upwards retracting can be immediately from not being with 14 releases to be transferred layer 28.Exactly, by during transferring step, construction platform 18 being positioned at than in high position, the position shown in Fig. 4 D, when pressing plate 20 is retracted, can will maintain in relatively constant position with 14.Can utilize independent fixing step subsequently.

In this fixing step, air knife 42 can be activated with from being with 14 releases to be transferred layer cooling layer 28 that transferred before 28.After being enough to that in the past layer material is cooled to the duration lower than temperature of fusion, this will be transferred layer and 28 maintains in fixed space position and adhere to 3D parts 22, and construction platform 18 reduces subsequently with from being with 14 releases to be transferred layer 28.

Can also transferred layer 28 from being with 14 to activate air knife 42 after peeling off and transferred layers 28 so that cooling-air is blown to.This transfers by quilt the averaging section temperature that layer 28 is cooled to expectation on one's own initiative.The scope of the example of the duration of applicable this active cooling step is from approximately 1.0 seconds to approximately 2.0 seconds, and this can be corresponding to transfer and the aligning of lower one deck 28.

As can be appreciated, layer 28 from suspending with 14 transfers to construction platform 18 during compression step.Otherwise, with 14 during transferring step the motion in the sense of rotation of arrow 30 may cause and be extruded layer 28 mispairing, cause potentially lower part quality.Adopt as service loop, as those disclosed in U.S. Patent Application No. 13/242,841, these time-outs during can regulating each to transfer step.As further illustrated in Fig. 4 B-4D, when this layer 28 is just transferred, lower one deck 28a can be positioned at well heater 32 places.This allow well heater 32 this layer 28 just transferred in 3D parts 22 under needed interval heats fully one deck 28a.After layer 28 is transferred and is cooling, for each succeeding layers of layer 28a and 3D parts 22 repeats identical process.

Fig. 5 A-5E diagram layer transfers assembly 133, and wherein the layer of system 10 transfers the replacement of assembly 33 (at Fig. 1,2, and shown in 4A-4D), and wherein the Reference numeral of corresponding component increases " 100 " than system 10.As shown in Figure 5A, layer transfers assembly 133 and comprises the mip rolls 120 that replaces pressing plate 20, and wherein mip rolls 120 is another exemplary heatable elements or can transfers component element by zone of heating, and is configured to rotate around fixed axis along with the motion with 114.Especially, mip rolls 120 can roll with 114 when the side of arrow 130 rotates up in the direction of arrow 156 on the 114b of rear surface.In certain embodiments, mip rolls 120 can be as the driven roller with 114.

As further shown, air ejector 142 (or other suitable cooling unit) is used for replacing air knife 42, and be positioned at 114 and mip rolls 120 between the downstream at interface.The top layer that air ejector is configured to after each transfers step, cooling-air to be blowed to 3D parts 122 is with cooling this layer on one's own initiative, as discussed below.

In this embodiment, construction platform 118 is supported by stand 134, and stand 134 is to be configured for along z axle and x axle to move construction platform 118 to produce the guide of reciprocal rectangular patterns, and wherein main motion is seesawing along x axle.Stand 134 can the command operation based on carrying out self-controller 124 by motor 136, and wherein motor 136 can be electro-motor, hydraulic system, baric systerm etc.Thereby applied pressure can be undertaken by construction platform 118 during each transfers step.

Before printing 3D parts 122, construction platform 118 and mip rolls 120 can be heated to their target temperature, as above discussed for construction platform 18 and pressing plate 20.Compare with pressing plate 20, heating element 140 mip rolls 120 can be heated to higher temperature (as, to averaging section temperature) because heat flows through partly with 114 and needs the relatively short times from mip rolls 120.

During printing, well heater 132 is by developing layer 128 and with 114 relevant range, be at least heated to the temperature of fusion of thermoplastic based powder.As shown in the figure, with 114, zone of heating 132 can be moved to the predetermined registration position along x axle subsequently.Stand 134 can upwards activate construction platform 118 subsequently with in conjunction with being with 114, with 114, the top layer of 3D parts 122 is pressed against on zone of heating 124, as shown in arrow 158.Alternatively, mip rolls 120 can be activated to run into top layer or the top surface of 3D parts 122 downwards.

As shown in Figure 5 B, this position at mip rolls 120 is squeezed in zone of heating 128 the top layer of 3D parts 122 and is with between 114.Although construction platform 118 keeps and is with 114 combinations, but stand 134 can above move construction platform 118(and 3D parts 122 along x axle in the direction (that is, identical direction and speed) of arrow 160 with the speed with synchronizeing with the speed of rotation of 114 directions at arrow 130 subsequently).This by with 114 and zone of heating 128 be squeezed between the top layer and mip rolls 120 of 3D parts 122.

As shown in Figure 5 C, this cause with 114 rear surface 114b on mip rolls 120, roll with by with 114 and zone of heating 128 folders lean against on the top layer of 3D parts 122.The temperature of fusion and the 3D parts 122 that due to layer 128, are heated to component materials are maintained at averaging section temperature place, are therefore extruded layer 128 and transfer to the top layer of 3D parts 122 in the similar mode of the mode to above discussing with layer 28 for 3D parts 22.

As further shown, when quilt is transferred the roll gap of layer 128 process mip rolls 120, be with 114 around mip rolls 120, to be wound around with the separated and disengaging from construction platform 118.This helps, from being with 114 releases to be transferred layer 128, allowing to be transferred layer 128 and keep adhering to 3D parts 122.In addition the top layer that, air ejector 142 blows to cooling-air 3D parts 122 when construction platform 118 moves through mip rolls 120 along x axle is transferred layer 128 to fix.By cooling-air being blowed to 3D parts 122 constantly transferring between step, can be cooled to averaging section temperature by being transferred layer 128, therefore make fixing step and active cooling step overlapping.

When construction platform 118 mobile 3 D parts 122 process mip rolls 120, stand 134 can activate construction platform 118(and 3D parts 122 downwards), as shown in arrow 162.As shown in Figure 5 D, stand 134 can move construction platform 118(and 3D parts 122 along x axle subsequently in the direction of arrow 164), along x axle, be back to reference position.As shown in Fig. 5 E, wish that construction platform 118 arrives reference positions when the next one is heated layer 128 and is positioned at above 3D parts 122.Repeat subsequently identical process, wherein stand 134 upwards activate construction platform 118 with by with 114 and the next layer 128 that is heated be squeezed between the top layer and roller 120 of 3D parts 122, as shown in arrow 166.Yet, in this step, to compare with compression step before, the height of the top surface of 3D parts 122 offsets downward as individual layer increment.

As can be appreciated, with reciprocal rectangular patterns, move construction platform 118(3D parts 122) allow be with 114 in rotation, to transfer step continuously.Especially, with the speed with synchronizeing with 114 speed of rotation, move construction platform 118, and use the mip rolls 120 rotate on the rear surface 114b with 114, allow rapidly (as, in approximately 0.1 second to approximately 0.5 second) transfer step and fixing step.This allows the scope of active cooling step is from approximately 1.0 seconds to approximately 2.0 seconds, and this can be heated corresponding to the next one transfer and the aligning of layer 28.Although back and forth rectangular patterns is described to the slightly pointed axial angle of tool (by arrow 160,162,164 and 166 restrictions) rectangular patterns, but stand 134 can be to have circle or oval reciprocal rectangular patterns and construction platform 118(and the 3D parts 122 that limit angle), if construction platform 118 during transferring step along x axis linear mobile.

Fig. 6 A-6F diagram layer transfers assembly 233, and it is the replacement that layer transfers assembly 133 (shown in Fig. 5 A-5E), and wherein the Reference numeral of corresponding component increases " 200 " than system 10.Layer transfers assembly 233 and can work to transfer the similar mode of assembly 133 with layer, and wherein construction platform 218 can move with reciprocal rectangular patterns.

Yet as shown in Figure 6A, layer transfers assembly 233 and comprises the fusing roller 220 of single mip rolls 120 substantially and discharge roller 268, wherein melt roller 220 and discharge in roller 268 each be configured to along with the motion with 214 is rotated around an axis.The use of independent a plurality of rollers (that is, fusing roller 220 and release roller 268) by the function of each roller separately, allows to optimize them for their specific purpose.For example, fusing roller 220 can be heated to the temperature of fusion of thermoplastic based powder, discharges roller 268 and can be maintained at quite low temperature and sentence and help from being with 214 to peel off and transferred layer 228.

As further shown, system 210 also comprises well heater 270 and 272 and air ejector 274.Fusing roller 220 and discharge separately forming of roller 268 independent transfer step and release steps, and allow to be coolingly fixed step transferring between step and release steps via what undertaken by air ejector 274.By postponing release steps, fusing roller 220 can be heated to the most applicable temperature of fusion of transferring step, rather than the temperature of compromising and being conducive to transfer and discharge in simultaneously.This has increased the interlayer adhesion force being transferred between layer 228.

Before printing 3D parts 222, construction platform 218 and fusing roller 220 can be heated to their target temperature.For example, construction platform 218 can be heated to averaging section temperature, and fusing roller 220 can be heated to the temperature of fusion of thermoplastic based powder.During printing, be with 214 to carry developing layer 228 through well heaters 232, well heater 232 is by developing layer 228 and with 214 relevant range, be at least heated to the temperature of fusion of thermoplastic based powder.

In addition, platen stand 234 in the direction of arrow 276 along x axle below well heater 270, move construction platform 218 along well heater 270 or through well heater 270.Well heater 270 can work in the mode identical with well heater 32 and 232, and the top surface of 3D parts 222 is heated to the temperature of rising, as the temperature of fusion place at layer material.

As shown in Figure 6B, with 214 lasting rotation and construction platform 218, move with the suitable registration along x axle zone of heating 228 is alignd with the top surface having heated of 3D parts 222.And, each in the top surface having heated of zone of heating 228 and 3D parts 222 has been through well heater 272, and well heater 272 can be configured to heat simultaneously and/or maintain the top surface having heated of zone of heating 228 and 3D parts 222 at the temperature of fusion place of layer material.This prevents that zone of heating 228 is cooling before arriving fusing roller 220, and carry out the next one temperature of the top surface having heated of 3D parts 222 is brought to before transferring step temperature of fusion place or near.In alternative embodiment, one or more in well heater 232,270 and 272 can be set to be configured in multiple directions (as, simultaneously towards the top surface of layer 228 and 3D parts 222) the single well heater of guiding heat.

Stand 234 can above move construction platform 218(and 3D parts 222 along x axle in the direction (that is, identical direction and speed) of arrow 276 with the speed with synchronizeing with the speed of rotation of 214 directions at arrow 230).This by cause with 214 rear surface 214b around 220 rotations of fusing roller with by with 214 and zone of heating 228 press from both sides and lean against on the top surface of 3D parts 222.This is in conjunction with construction platform 218 and be with 214, and in the position of fusing roller 220, zone of heating 228 is squeezed in to the top surface having heated of 3D parts 222 and is with between 214.

Because each in the top layer having heated of layer 228 and 3D parts 222 is heated to the temperature of fusion of layer material, therefore zone of heating 228 transfers the top surface having heated to 3D parts 222 with high-level layer-to-layer adhesion.By separately melting roller 220 and discharging roller 268, via air ejector 274, carry out betwixt cooling step, layer transfers assembly 233 and allows that layer is heated to the best and transfer interface temperature, and is cooled to the temperature of fixing this layer before discharging.For example, for transfer together layer transfer interface temperature can the about temperature of fusion of layer material (as, approximately 200 ℃) locate.It is interface-cross-linked to promote that the degree of polymer molecule phase counterdiffusion of layer is transferred in this quite large increase, also maintains the dimensional accuracy of 3D parts 222 simultaneously.

As shown in Figure 6 C, after extruding fusing roller 220, and construction platform 218 keeps and is with 214 combinations simultaneously, is with 214, construction platform 218 and 3D parts 222 are through air ejectors 274.Air ejector 274 can the mode identical with air ejector 142 and 242 work, and for cooling rear surface 214b side, is with 214.In alternative embodiment, air ejector 274 can be multiple different cooling unit, as refrigeration unit, liquid cooling unit etc.

As mentioned above, if transferred layer 228, keep too hot, its part can keep adhering to the front surface 214a with 214, rather than discharges neatly from being with 214.Like this, with air ejector 274 salbands 214, allow with 214 front surface 214a and the interface of being transferred between layer 228 coolingly, make to be transferred layer 228 and keep adhering to 3D parts 222 and discharge neatly from being with 214.This also partly helps the active cooling of 3D parts 222,3D parts 222 are maintained to the averaging section temperature place lower than its deformation temperature.

As further illustrated in Fig. 6 D, when being transferred the gap of layer 228 process release roller 268, be with 214 around discharging roller 268 rotations with the separated and disengaging from construction platform 218.This help from being with 214 releases to be transferred layer 228, allowing to be transferred layer 228 and keeps adhering to 3D parts 222 in " up-stripping " step.In addition,, when construction platform 218 moves through release roller 268 along x axle, air ejector 242 blows to cooling-air the top layer of 3D parts 222.This will be transferred layer 228 and will be cooled on one's own initiative averaging section temperature, as mentioned above.

When construction platform 218 mobile 3 D parts 222 processes discharge roller 268, stand 234 can activate construction platform 218(and 3D parts 222 downwards), as shown in arrow 278.For example, construction platform 218 can offset downward gradually with individual layer increment.As shown in Fig. 6 E, stand 234 can move construction platform 218(and 3D parts 222 along x axle in the direction of arrow 280), along x axle, be back to reference position.

As shown in Fig. 6 F, wish that construction platform 218 arrives reference position, for suitably aiming at lower one deck 228.Can repeat identical process for remaining every one deck 228 of 3D parts 222 subsequently.Layer transfers assembly 233 provides following benefit: for increasing the temperature of fusion of interlayer adhesion force, transfer together layer, simultaneously before discharging with 214 also fully the front surface 214a of salband 214 and transferred interface between layer 228 with by layer 228 fixing in place in, and by helping from 214 peel off and promote clean release.

In addition, for each printable layer 228, being combined in of air ejector 242 and 274 (or other cooling unit) removed substantially from heating element 232,270 before printing lower one deck 228, and 272 and the heat that adds from the fusing roller 220 of heating.This active cooling is provided by heat substantially that provided by every one deck 228, thereby after printable layer 228, provides the heat built-up being substantially zero at each.Like this, during whole printing, 3D parts 222 can be maintained substantially to the averaging section temperature place lower than its deformation temperature.Further, after the well heater 270 and/or 272 that adopts layer to transfer assembly 233 is peeled off, can make the topsheet surface temperature rising of having printed 3D parts 222 be back to temperature of fusion, for the best of lower one deck 228, transfer.

The system 10 of transferring assembly 33,133 and 233 with layer is applicable to from thermoplastic based powder, printing 3D parts (with any supporting construction) with high speed and good parts resolution.In certain embodiments, system 10 can with aim at accurately with at least about 40 layers of per minute (as, approximately 50 layers of per minute) speed is printed the layer of 3D parts, the scope of layer thickness is from approximately 5 microns to approximately 125 microns, and along the layer size of y axle up at least about 51 centimetres (approximately 11 inches).For example, system 10 can be printed 3D parts with approximately 3 inches of speed hourly aspect the height along vertical z axle.

The resolution of 3D parts can also change based on printing speed.For example, can be with each 3D parts of " high-quality " resolution printing, wherein system 10 is moved with slower speed, but prints with lower bed thickness.Alternatively, can be with " draft quality " resolution printing 3D parts, wherein system 10 is with speed operation faster, but prints with larger bed thickness.And, can print 3D parts with " gray level ", wherein low-density component materials is developed.Also can be in conjunction with multiple resolution and speed therebetween.In each in these situations, controller can be adjusted institute's applied pressure, temperature and/or duration of contact to consider different printing speed during transferring step.

System 10 is illustrated as to be configured for from thermoplastic based powder prints 3D parts (as, 3D parts 22,122 and 222).Yet, the accumulation manufacturing system of present disclosure also can be configured for from be derived from the multiple component materials of thermoplastic based powder and/or propping material (as, Multiple components and/or color) print 3D parts and/or supporting construction.The example of suitable multi-material system comprises those disclosed in U.S. Patent Application No. 13/242,669 and 13/242,841.

In certain embodiments, controller 24 can monitor temperature and the duration of contact of institute's applied pressure, layer during transferring step, to maximize or otherwise to increase from layer table and be transferred to the effect of construction platform from transition zone.In open loop embodiment, for given component materials and the whole speed of printing, one or more in institute's applied pressure, temperature and duration of contact can be preset parameters.

Alternatively, in closed loop embodiment, controller 24 can adopt one or more process control loops to adjust one or more in these parameters in response to the signal monitoring.For example, controller can be in response to the variation adjustment of the temperature detecting of the variation of the pressure detecting and/or described layer by pressing plate 20 or construction platform 118 and 218 applied pressures.And controller 24 can be adjusted the duration of contact transferring during step, with the temperature variation of layer of compensation and/or the fluctuation of exerting pressure monitoring.

As shown in Figure 7, in certain embodiments, system 10 can also comprise chamber 284, and chamber 284 surrounding layers transfer assembly 33 and extend, and can be defined for print 3D parts 22 can enclosed environment.Although be illustrated for layer and transfer assembly 33, chamber 284 is suitable for equally layer and transfers assembly 133 and 233.Chamber 284 is the controlled chambers of temperature, and it provides larger control to active cooling step.For example, chamber 284 can be maintained to the averaging section temperature place of 3D parts 22.

In these embodiments, chamber 284 can be partly around z pillow block frame 34 be with 14, allow z pillow block frame 34 and with 14 walls that extend through chamber 284.In alternative embodiment, well heater 32 can be positioned at outside and the upstream of chamber 284.In other alternative embodiment, chamber 284 can be positioned at below pressing plate 20, allows construction platform 18 to reduce and enters in chamber 284.These embodiment further help 3D parts 22 to maintain the averaging section temperature place lower than its deformation temperature.

As further illustrated in Fig. 7, layer transfers assembly 33,133 or 233 can also comprise pressure transducer (as, pressure transducer 286) and/or capacitive transducer (as, capacitive transducer 288), each sensor is configured on one or more communication line (not shown) and communicates by letter with controller 24.Pressure transducer 286 is to be configured to measure the one or more sensor modules that transfer pressure that are applied to (or between construction platform 118/218 and a plurality of roller 120/220) between construction platform 18 and pressing plate 20, allows controller 24 to adopt one or more process control loops to monitor transferring pressure and adjusting construction platform 18 and/or the height of pressing plate 20 of applying.The example that is applicable to the sensor module of pressure transducer 286 comprises the one or more strainmeters that are maintained on construction platform 18 and/or pressing plate 20.

Capacitive transducer 288 is to be configured to measure the one or more capacitive transducer assemblies that are applied to the resistance of (or between construction platform 118/218 and a plurality of roller 120/220) between construction platform 18 and pressing plate 20.For example, during transferring step, capacitive transducer 288 electric current from platen 18 to pressing plate 20 (or vice versa) of can inducting, and measure the printable layer that passes through 3D parts 22 28 that produces and with the intensity of 14 electric current.Because the thickness with 14 is constant, along with 3D parts 22 are grown by the printing of successive layers 28, the electric current producing will reduce.

Therefore, the height of the suitable monitoring of capacitive transducer 288 3D parts 22 and the quantity that is transferred to the layer 28 of construction platform 18.This allows controller 24 applied pressure during follow-up compression step that calculates to a nicety, rather than only depends on the computed altitude of individual layer increment.This accurately predicting allows construction platform 18 to be increased to rapidly expection height, rather than only depends on the feedback signal from pressure transducer 286.

Construction platform 18,118 and 218, each in pressing plate 20 and a plurality of roller 120 and 220 can also comprise the one or more temperature sensor (not shown) that are configured for the temperature of measuring respectively construction platform and pressing plate/roller, allows controller 24 to hold them in said temperature place.In other alternative embodiment, system 10 can comprise the temperature sensor (not shown) that is configured for the temperature of measuring 3D component layer.For example, system 10 can comprise for adopting acoustic thermometry measurement to transfer the ultrasonic transducer of the temperature of layer 28 by the temperature of layer 28 with 14 maintenances or the previous quilt of 3D parts 22.

In certain embodiments, controller 24 and/or main frame 26 can receive for the operator scheme with different mode operating system 10 and select.For example, user can select operating mode, as high-quality is printed, draft quality is printed and gray level, as mentioned above.Alternatively, system 10 can receive the pattern that operator scheme is selected or system produces (as, the default value that high-quality is printed) of acquiescence.Alternatively (or additionally), can operator schemes selection that these receive be set the geometry based on 3D parts, for example, and as mentioned above, if 3D parts have little cross-sectional area and/or fine-feature details.

When receiving these operator schemes and select, controller 24 and/or main frame 26 can the operator scheme based on receiving select to be provided for transferring the parameter of transferring of step.For example, operator scheme that can be based on receiving is selected that each is set and is transferred transferring pressure, temperature and duration of step.This provides larger control to transferring step in operating system 10 when improving printing precision and/or printing speed.

System 10 subsequently can from thermoplastic based powder to 3D parts layer carry out imaging (as, with EP instrument 12 developing layers), imaging layer is transferred to transfer medium, at imaging layer, when remaining on transfer medium, heat imaging layer, and based on the set parameter of transferring, zone of heating is transferred to the surface to three-dimensional part.

It is in certain embodiments, set that to transfer transfer pressure, temperature and/or the duration that parameter allows each to transfer step be different in different transferring between step.For example, if the first of 3D parts comprises simple component geometry structure, the second portion of 3D parts comprises fine-feature geometry, controller 24 and/or main frame 26 can arrange and transfer parameter, make for form simple component geometry structure layer (as, the higher pressure that transfers) be different from for form fine-feature geometry (as, the lower pressure that transfers) layer transfer.

Fig. 8 and 9A-9C diagram be applicable to being with 14 (at Fig. 1,2 and 4A-4D shown in) and be applicable to equally with 114 (shown in Fig. 5 A-5E) with the embodiment of 214 (shown in Fig. 6 A-6F).In the embodiment show in figure 8, be with 14 to be sandwich tapes, comprise layer or film 290 (limiting front surface 14a) and base portion 292 (limiting rear surface 14b).

What wish is that film 290 and base portion 292 are derivative from following material, this material is applicable to the layer 28 of parts (or support) material to be transferred to construction platform 18 from EP instrument 12, fusion temperature place at parts and propping material is heat-staple, and in by repeatedly heating and cooling, tolerates the continued operation of high rotation speed during heating active cooling step.

Film 290 is derivative from one or more low-surface-energy materials, thereby allows the layer 28 receiving from front surface 14a, to be released into construction platform 18 on one's own initiative.The example that is applicable to the material of film 290 comprises one or more fluorinated polymers, as teflon (PTFE), PEP and perfluoroalkoxy.The example of suitable commercial fluorinated polymer comprises the PTFE with trade name " TEFLON " that can obtain from the E.I.du Pont de Nemours and Company in German Wilmington city.

Base portion 292 is from promote thermoplastic based powder material derived to one or more of the good electrostatic attraction of front surface 14a via triboelectric charge.The example that is applicable to the material of base portion 292 comprises one or more polyimide materials, as those materials with trade name " KAPTON " that can obtain from the E.I.du Pont de Nemoursand Company in German Wilmington city, it can be doped with for promoting one or more conductive materials of triboelectric charge.In certain embodiments, with 14 one or more extra plays that can also comprise between film 290 and base portion 292, as one or more laminated film tack coats.

Fig. 9 A-9C diagram for a plurality of driven rollers with system 10, receive with 14 alternative embodiment.As shown in Figure 9 A, with 14 front surface 14a, can comprise receiving area 294 and be positioned at the fringe region 296 of the contrary cross side of receiving area 294.Receiving area 294 is regions of the layer 28 that is kept for shifting between EP instrument 12 and construction platform 18 of front surface 14a.Fringe region 296 is regions that one or more driving mechanisms can receive rotating band 14.

For example, one or more rollers (as, a plurality of rollers 16, mip rolls 120, fusing roller 220, discharges roller 268 and/or any service loop roller) can in conjunction with front surface 14a and/or rear surface 14b, to guarantee a plurality of rollers, not disturb developing layer 28 in edge region 296 places.In certain embodiments, multipair relative roller (not shown) can edge region 296 places simultaneously in conjunction with front surface 14a and rear surface 14b with clamping band 14 and in the direction of arrow 30 rotating band 14.

Can adopt scrambler mark 298 to maintain the shaft alignement along x.Scrambler mark 298 can along x axle with preset increment by preliminary making on front surface 14a and/or rear surface 14b, or can adopt developing layer 28 to print, to identify developing layer 28 along the relative position of x axle.System 10 can also comprise for one or more optical readers of position encoder mark 298 when rotating up in the side of arrow 30 with 14 (as, optical reader 299).

Alternatively, as shown in Figure 9 B, with 14 arrays that can comprise hole 300 or other opening, its contiguous lateral edge with 14 extends through film 290 and base portion 292.Hole 300 is configured to the reciprocating gear tooth combination with one or more rollers (as, a plurality of rollers 16, mip rolls 120, fusing roller 220, discharges roller 268 and/or any service loop roller), thereby with traction feeding mode rotating band 14.In this embodiment, if needed, also can adopt scrambler mark 298 to maintain the shaft alignement along x.Alternatively, hole 300 itself can be used as scrambler mark in an identical manner.System 10 can also comprise for one or more optical readers in position encoder mark 298 and/or hole 300 when rotating up in the side of arrow 30 with 14 (as, optical reader 299).

Fig. 9 C illustrates another alternative embodiment, wherein with 14, comprises the rear flank 302 laterally extending along rear surface 14b.Flank 302 is configured to the reciprocating gear tooth combination with one or more rollers (as, a plurality of rollers 16, mip rolls 120, fusing roller 220, discharges roller 268 and/or any service loop roller), thereby with Timing Belt mode rotating band 14.In this embodiment, if needed, also can adopt the scrambler mark corresponding to scrambler mark 298 to maintain the shaft alignement along x.Alternatively, flank 300 itself can be used as scrambler mark in an identical manner.System 10 can also comprise for one or more optical readers of position encoder mark and/or hole flank when rotating up in the side of arrow 30 with 14 (as, optical reader 299).

Fig. 9 A-9C illustrates the exemplary combination mechanism with 14, and it allows to be combined with one or more driving mechanisms of system 10 with 14.Yet, alternatively, with 14, can comprise the different combining mechanism that may need as particular design.

Figure 10-12nd, the process flow diagram of the implementation method of the layer transfer technology of present disclosure, can adopt system 10 to carry out this implementation method.Figure 10 graphic technique 310, can adopt have layer transfer assembly 33 (at Fig. 1,2 and 4A-4D shown in) and/or the layer system 10 of transferring assembly 133 (shown in Fig. 5 A-5E) carry out the method 310.As shown in the figure, method 310 comprises step 312-324, and relates at first as adopted EP instrument 12 to develop or imaging layer (step 312) otherwise.Imaging layer subsequently can from the primary importance of EP instrument 12 to layer transfer assembly (as, layer transfers assembly 33 and 133) second place located transfer to transfer medium (as, be with 14 and 114) upper (step 314).

Arrive before layer transfers the second place at assembly place, described layer be instructed to be heated to thermoplastic based powder temperature of fusion (as, at well heater 32 and 132 places) (step 316).Once arrive layer, transfer assembly, in combination step, transfer subsequently and fix zone of heating (step 318).

For example, for layer, transfer assembly 33, pressing plate 20 can be in conjunction with construction platform 18 to transfer zone of heating 28 the top surface of 3D parts 22.Because pressing plate 20 can be heated to the temperature lower than temperature of fusion, therefore pressing plate 20 and can salband 14 and transferred the interface between layer 28 with the contact between 14 rear surface 14b, with respect to being transferred layer 28 bounding force to the surperficial 14a with 14, increase the bounding force that is transferred the polymkeric substance of phase counterdiffusion in layer 28 and 3D parts 22, thereby the layer that transferred that adheres to 3D parts is maintained in fixed space position.

As by retraction pressing plate 20 and/or construction platform 18, or by be with 114 around mip rolls 120 be wound around two will be with 114 separated from construction platform 118, transferred and fix layer can discharge (step 320) from transfer medium subsequently.Above-mentioned fixing step allows to be transferred layer and from transfer medium, discharges neatly and keep adhering to 3D parts.

Subsequently (as, adopt air knife 42 and air ejector 142) cooling 3D parts (step 322) on one's own initiative.As mentioned above, due to imaging system (as, system 10) can with than heat, diffuse through 3D parts can variable resistance the faster speed of speed print described layer, therefore heat can accumulate in 3D parts, if do not solved, the deformation temperature that this can surpass 3D parts, causes that the main body of 3D parts is enough softening, reduces its structural integrity.This soft parts follow-up transfer step during follow-up transferring under pressure of applying may be out of shape.

In order to solve this topic when maintaining fast printing speed, can transfer between step 318 on one's own initiative cooling 3D parts 3D parts are maintained to the averaging section temperature place lower than the deformation temperature of 3D parts at each.Subsequently can be for every one deck repeating step 312-324 of 3D parts, until complete printing (as shown in arrow 324).By every one deck being at least heated to the temperature of fusion of thermoplastic based powder, next to transfer/fix, and active cooling, permission system 10 is printed 3D parts with good part quality and intensity (as, z axle intensity).

Figure 11 graphic technique 326, it is similar to method 310 (shown in Figure 10), and can transfer assembly 233 (shown in Fig. 6 A-6F) the system 10 execution the method 326 of (and keeping after pressing plate 20 retractions and transferred assembly 33 by having layer in transferring layer 28 embodiment contacting with 14) by having layer.Method 326 comprises step 328-342, and mode that wherein can be identical with the corresponding steps with method 310 carry out step 328,330,332,338,340 and 342.

Yet, the transferring and fixing step 318 of the combination of replacement method 310, method 326 comprise separately transfer step 334 and fixing step 335.For example, layer transfers assembly 233 and comprises the roller of heat fused 220 (for transferring step 334) that separated by air ejector 274 (for cooling or fixing step 336) and release roller 268 (for release steps 338).This allows at heating steps 332 places and during transferring step 334, described layer is heated to the best to transfer interface temperature, is cooled to subsequently the temperature of (at fixing step 336 places) fixing described layer before release steps 338 places discharge.This degree that increases considerably the polymer molecule phase counterdiffusion of being transferred layer is interface-cross-linked to promote, also maintains the dimensional accuracy of 3D parts 222 simultaneously.

And, during release steps 338, can help to discharge and transferred layer from transfer medium.For example, by increase with 214 and construction platform 218 between the angle of departure (this increase to be transferred layer 228 from 214 easiness of peeling off), discharge roller 268 and can help from being with 214 releases to be transferred layer 228.

As further illustrated in Figure 11, active cooling step 340 can be the optional step (as shown in dotted line 344) of method 326.For example, instead, system 10 can move to allow heat to spread from 3D parts with lower print speed.Yet as mentioned above, active cooling step 340 is for wishing to maintain the structural intergrity of 3D parts when printing at a high speed.

Figure 12 graphic technique 346, it is similar to method 310 (illustrating in Figure 10 China) and method 326 (shown in Figure 11), and can carry out the method 346 by having layer system of transferring assembly 233 (shown in Fig. 6 A-6F) 10.Method 346 comprises step 348-364, and mode that wherein can be identical with the corresponding steps with method 326 carry out step 348,350,352,356,358,360,362 and 364.

Yet method 346 also comprises step 354, wherein before transferring step 356, also preheat top surface or the layer of 3D parts.For example, adopt layer to transfer assembly 233, well heater 270 and 272 can at least be heated to the top surface of 3D parts 222 or layer the temperature of fusion of thermoplastic original washing powder art.Because each in the layer 228 of 3D parts 222 and top surface/layer of having heated is heated to the temperature of fusion of layer material, so the zone of heating 228 being extruded transfers the top surface/layer (during transferring step 358) of the 3D parts 222 of heating with high-caliber layer-to-layer adhesion.

And, by separately melting roller 220 and discharging roller 268, at fusing roller 220 and release roller 268, via air ejector 274, carry out cooling or fixing step 358, layer transfers assembly 233 and allows that described layer is heated to the best and transfer interface temperature, and described layer is cooled to the temperature of fixing described layer before method.This degree that increases considerably the polymer molecule phase counterdiffusion of being transferred layer is interface-cross-linked to promote, also maintains the dimensional accuracy of 3D parts simultaneously.

Example

Therefore in the example being next only intended to as explanation, more specifically described present disclosure, the numerous modifications and variations in the scope of present disclosure will be obvious for a person skilled in the art.

Example 1

Printing for example 1, employing is corresponding at Fig. 1,2 print 3D parts with the system shown in 4A-4D, the accumulation manufacturing system with movable pressing board and vertical actuatable construction platform, and movable pressing board is heated with each in vertical actuatable construction platform.From ABS component materials, print 3D parts, wherein every one deck is developed by electrofax instrument and is transferred to around the rotatable transition zone of service loop structure Cheng Huan.Developing layer is carried to infrared heater by transition zone, this layer is heated to the temperature of fusion of ABS component materials.

Zone of heating is transferred to subsequently construction platform and aligns on construction platform.Pressing plate is activated that downwards zone of heating is transferred on the layer (transferring to construction platform concerning initiation layer) previously having been transferred of 3D parts.Pressing plate is retracted subsequently, and this peels off described layer neatly from transition zone, allows described layer to keep transferring the parts to 3D.

From the cooling-air of air knife, be also directed to the top layer of 3D parts.This is removed additional heat from transferring layer, and so that the averaging section temperature of the structural intergrity that maintains 3D parts to be provided, wherein 3D parts can be because heat built-up is subsided or melts.Every one deck for 3D parts repeats this process.Air knife and pressing plate successfully maintain the deformation temperature lower than 3D parts by averaging section temperature during whole printing.The 3D parts that produce present good parts resolution, intensive filling and good dimensional integrity.

Example 2

For the printing of example 2, adopt corresponding in the system shown in Fig. 5 A-5E, there is all accumulation manufacturing systems of heated mip rolls and movable construction platform and print 3D parts.From ABS component materials, print 3D parts, wherein every one deck is developed by electrofax instrument and is transferred to around the rotatable transition zone of service loop structure Cheng Huan.In these examples, service loop is used for protecting transition zone to avoid tension stress impact.Developing layer is carried to infrared heater by transition zone, this layer is heated to the temperature of fusion of ABS component materials.

Zone of heating is transferred to subsequently construction platform and aligns on construction platform.Construction platform is actuated upward zone of heating to be transferred on the layer (transferring to construction platform concerning initiation layer) previously having been transferred of 3D parts.Especially, upwards activate construction platform by zone of heating and transition zone are squeezed between construction platform (or leaning against on the layer previously having been transferred of 3D parts) and mip rolls.Construction platform moves with the speed of synchronizeing with transition zone subsequently, and in downstream position, is released subsequently.This peels off described layer neatly from transition zone, allows described layer to keep transferring the parts to 3D.

From the cooling-air of reference position, be also drawn towards the top layer of 3D parts.This is removed additional heat so that the averaging section temperature of the structural intergrity that maintains 3D parts to be provided from transferring layer, and wherein 3D parts can be because heat built-up is subsided or melts.Construction platform is moved back into its reference position subsequently, and repeats this process for every one deck of 3D parts.In these these examples, air ejector also successfully maintains the deformation temperature lower than 3D parts by averaging section temperature during whole printing.The 3D parts that produce present good parts resolution, intensive filling and good dimensional integrity.

Comparative example A and B

For the printing of comparative example A and B, the identical accumulation manufacturing system that adopts respectively as use in example 1 and 2 is printed 3D parts.Yet, for comparative example A and B, omitted air knife or sprayed cooling.Otherwise, as mentioned above as carried out in an identical manner this process in example 1 and 2.

For the printing of comparative example A and B, at each, printed before 3D parts complete, printable layer starts compression and flattens.As mentioned above, this it is believed that it is that heat by gathering in printable layer causes, this heat can not be in each diffusion fully between printable layer.The heat gathering makes the main body of 3D parts softening, causes that it compresses during transferring step follow-up.This causes the 3D parts of distortion.

Like this, the layer transfer technology that comprises active cooling of present disclosure is conducive to adopt electrophotography to print 3D parts with high speed.This active cooling is successfully carried out from each fused layers, to remove the heat being increased before the transferring of lower one deck.This permission maintains the averaging section temperature place lower than their deformation temperature by the 3D parts of the system print in example 1 and 2, but this averaging section temperature is enough high to promote good layer-to-layer adhesion and to reduce curling.

Although described present disclosure with reference to preferred embodiment, it will be recognized by those skilled in the art, in the situation that not departing from spirit and scope of the present disclosure, can change in form and details.

Claims (14)

1. for printing an accumulation manufacturing system for three-dimensional part, this accumulation manufacturing system comprises:

Transfer medium, is configured for the imaging layer that receives and shift thermoplastic based powders from imaging tool;

Well heater, is configured for the imaging layer on transfer medium is heated to at least temperature of fusion of thermoplastic based powder;

The layer that comprises construction platform transfers assembly, and this layer transfers assembly and is configured in mode successively zone of heating is transferred on construction platform with printing three-dimensional part; With

Cooling unit, be positioned at layer transfer the downstream of assembly, and be configured on one's own initiative cooling transferred layer the three-dimensional part of having printed is remained on to the averaging section temperature place of the deformation temperature that is less than about greatly three-dimensional part.

2. accumulation manufacturing system according to claim 1, wherein imaging tool comprises electrofax instrument, and wherein, accumulation manufacturing system also comprises described electrofax instrument, described electrofax instrument is configured from thermoplastic based powder development imaging layer.

3. accumulation manufacturing system according to claim 1, its middle level transfers that assembly comprises can heated platen, can heated platen be configured for zone of heating is transferred to the previous quilt of the three-dimensional part of having printed and transfers layer.

4. accumulation manufacturing system according to claim 1, wherein transfer medium comprises sandwich tape.

5. accumulation manufacturing system according to claim 1, also comprises and is configured at least one stand that moves construction platform with reciprocal rectangular patterns.

6. accumulation manufacturing system according to claim 5, wherein transfer medium comprises rotatable transfer medium, and wherein, described reciprocal rectangular patterns comprises that construction platform is with the motion of speed and the direction of the rotary synchronous with rotatable transfer medium.

7. accumulation manufacturing system according to claim 1, its middle level transfer assembly also comprise be arranged on transfer medium rear side can warm-up mill.

8. accumulation manufacturing system according to claim 7, wherein can comprise fusing roller by warm-up mill, and wherein, layer transfers assembly and also comprises:

Discharge roller, be arranged on the rear side of transfer medium, on the moving direction of transfer medium, be positioned at the downstream of fusing roller; With

The second cooling unit, is configured for cooling fusing roller and discharges the transfer medium between roller.

9. accumulation manufacturing system according to claim 8, wherein melts roller and is configured for and is heated at least temperature of fusion of thermoplastic based powder.

10. for printing an accumulation manufacturing system for three-dimensional part, this accumulation manufacturing system comprises:

Imaging tool, is configured for the imaging layer of development thermoplastic based powdery thermoplastic material;

Construction platform;

Rotatable band, is configured for to receive from the imaging layer of imaging tool and by imaging layer and is transferred to construction platform;

Well heater, the sense of rotation based on rotatable band is positioned at upstream with respect to construction platform, this well heater be configured to by rotatable with on imaging layer be heated at least temperature of fusion;

Can warm-up mill, be configured for zone of heating is transferred on the layer previously having been transferred of the three-dimensional part being maintained on construction platform; With

Cooling unit, the sense of rotation based on rotatable band is positioned at downstream that can warm-up mill.

11. accumulation manufacturing systems according to claim 10, wherein rotatable band comprises sandwich tape.

12. accumulation manufacturing systems according to claim 10, also comprise and are configured at least one stand that moves construction platform with reciprocal rectangular patterns.

13. accumulation manufacturing systems according to claim 10, wherein can comprise fusing roller by warm-up mill, and wherein, accumulation manufacturing system also comprises the release roller that is positioned at cooling unit downstream.

14. accumulation manufacturing systems according to claim 13, also comprise the second cooling unit, described the second cooling unit be configured on one's own initiative cooling transferred layer the three-dimensional part of having printed is remained on to the averaging section temperature place of the deformation temperature that is less than about greatly three-dimensional part.